The present invention relates to steels having high wear resistance and low friction surfaces and methods of producing these surfaces on steel.
In the past, the wear resistance of steel surfaces has been improved by subjecting the steel to a high temperature process in which a wear resistant coating is bonded to the surface or an element such as, carbon and/or nitrogen, is thermally diffused into the steel surface to locally increase the hardness of the steel itself in a relatively wide layer extending inwardly from the steel surface.
More recently, the use of ion implantation as a means for improving the wear resistance of steels and other alloys has begun to be explored. Ion implantation involves the implantation of a high energy, typically 10-400 keV, ionized species of atom or molecule into the surface being treated. The implanted ions are distributed in a relative thin band in a gaussian-like manner beneath the treated surface and produce a layer of irradiation hardened material in their wake. Thermal diffusion of the implanted species is insignificant since the process is carried out at a low temperature. Examples of ion implantation in steels are described in U.S. Pat. Nos. 3,900,636 and 3,832,219.
While improvements have been made in the wear and frictional properties of steel surfaces by the above processes, there still exists a need to provide further enhancement and optimization of these properties.